Paleoecological History of Maplecrest Fen, Catskill Mountains, (NY, USA) from Deglaciation to the Industrial Age

Aim: To develop the palaeoecological and palaeoclimatic history of Maplecrest Fen, Greene County, NY.

Location: Catskill Mountains, New York.

Time Period: 13,500 calendar years to present (ybp, present = 1950).

Taxon: Angiosperms, gymnosperms and bryophytes.

Methods: We used pollen and spore analysis, macrofossil analysis, loss-on-ignition (LOI) and X-ray fluorescence (XRF) analysis of a 7.8 m sediment core from the Fen along with AMS radiocarbon dates retrieved from the identified terrestrial macrofossils.

Results: Late-glacial and Holocene vegetational change from ice withdrawal reveals the development of a shallow lake and then fen to the present. The boreal spruce (Picea), fir (Abies) and paper birch ((Betula papyrifera) pollen signature near the base of the core (Zone M2) suggest a Younger Dryas (YD) signal overtopping warmer Allerod aged basal sediments. The early Holocene white pine (Pinus strobus) is followed by increases in hemlock (Tsuga) and beech (Fagus), ushering in a moister climate. About 5200 ybp drought is indicated by the well-known hemlock biostratigraphic decline in the Northeast. Drepanocladus moss and stonewort (Chara) shift to sedges (Carex) and violets (Viola) locally present. For the next 5000 years, the vegetation will remain relatively stable with lower temperatures suggested by the return of spruce and fir. Ragweed (Ambrosia) rise along with other weedy taxa marks European settlement near the top 50 cm of the core, along with a striking increase in anthropogenic lead, as seen using X-ray fluorescence.

Main Conclusions: Deglaciation began in the Catskills at a high elevation about 13,500 years ago and recession of ice from the Laurentide margin proceeded at about 0.1 km/year. Temperature shifts promoted changes in the boreal forest including warming and cooling, and drought and wetter intervals both appear in the Holocene history but do not appear to be easily forecast as climate continues to warm.